It wouldn't kill you to (do something).

People use this phrase to complain about someone not helping with chores like cooking, cleaning, yard work, etc.:

It wouldn't kill you to help out around the house sometimes, you know.

This means "You can (and should) help with the housework."

You can also phrase your complaint as a question:

Would it kill you to straighten up your desk every now and then?

You can use the phrases for other activities like exercise too:

It wouldn't kill you to do a few situps.

a load of laundry

"Laundry" are clothes that are being cleaned. You can count laundry by the amount that you put into the washing machine at one time. This amount is called a "load":

This load is almost finished. I'll let you know when it's done.

every now and then

"Every now and then" means "sometimes":

My mom still sends me packages from home every now and then.

I don't really play golf, but I do like to go hit balls on the driving range every now and then.

It wouldn't (do something), would it?

This is a tag question. You use this to confirm that what you're saying is true.